The art of producing foamed metal, ceramic or glass articles is highly developed. Many and various techniques are available for using foaming agents to produce a continuous output product in the form of a pipe or panel.
U.S. Pat. Nos. representative of this art include:
2,937,938--Fiedler et al.--May 24, 1960; PA1 3,473,904--Kraemer et al.--Oct. 21, 1969; PA1 3,527,587--Velev et al.--Sept. 8, 1970; PA1 3,574,583--Goldsmith--Apr. 13, 1971; PA1 3,607,170--Molesak--Sept. 21, 1971; and PA1 4,124,365--Williams et al.--Nov. 7, 1978.
When the output product is in the form of glass sheets or panels, various skin characteristics and shaping operations can be achieved by tempering processes in the drawing, shaping and cooling operations as represented for example by U.S. Pat. Nos. 4,046,543--Shields--Sept. 6, 1977 and 4,092,141--Frank et al.--May 30, 1978.
Other techniques are known in processing glass or foam which include the agitating of the molten materials and the removal of bubbles from the molten glass before further processing. U.S. Pat. Nos. representative of this art are 3,826,303--Jorema et al.--July 30, 1974; 3,960,532--Lazet--June 1, 1976; and 3,628,937--Schott--Dec. 21, 1971.
The latter patent also provides a method of forming foamed glass panels by introduction of gaseous bubbles into molten glass.
Although such patents as Goldsmith U.S. Pat. No. 3,574,583, above mentioned, recognize the insulating value of foamed glass and glass blocks or bricks are well known as construction materials, there has been a deficiency in the art in producing any long wear glass building material suitable as a building panel that will give life without protective coatings when exposed to atmosphere as glass does and yet have foam light-weight insulating properties. Further building material requirements not found in foamed glass products of the prior art are weight bearing strength, fracture, crack and shatter resistance to impact.
It is therefore a general object of this invention to improve the state of the art by providing versatile foam articles which can be used as long-life load-bearing construction materials suitable for exterior use with insulation properties, and methods of manufacturing such articles.
Further objects, features and advantages of the invention will be found throughout the following description, claims and accompanying drawings.